Apparatus and a method for assembling slats of a venetian blind

Abstract

An apparatus and a method for assembling the slats of a venetian blind in which slats are fed in turn into the venetian blind ladders and are raised to a first position sequentially to form, at that first position, a stack of assembled slats. The length of stroke of the lifting mechanism, preferably a linear motor, is restrained by an abutment which is removed as the last slat of a stack is being lifted, so that the whole stack is then lifted to a higher position at which it is retained and the ladders are moved past the slat feed point so that no slats are inserted therein. The next stack of slats is then formed at the first position and before it is completed, the ladder means are cut between the first and second positions.

We claim: 
     
       1. An assembly apparatus for assembling slats of a venetian blind in the ladder means of the blind, said apparatus comprising, in combination: (a) a first guide for guiding slat material in a slat feed direction;   (b) slat feeding means for moving slats through said apparatus;   (c) at least two assembly stations, each assembly station including: (i) a second guide for guiding a slat or a slat material assembled in said ladder means in a direction transverse to said feed direction;   (ii) a lifting element for moving each slat, after assembly into said ladder means in said transverse direction along said second guide, to a first position and by a distance effective to align the next rung of the ladder means with the first guide;   (iii) first retaining means to retain slats so lifted in said first position;   (iv) drive means to move said lifting element;   (v) control means to control the drive means effective to cause them to move said lifting element only by said distance, to move a slat to said first position;   (vi) intermittently operable means to over-ride said control means, effective to enable said drive means to lift a stack of slats held by said first retaining means to a second position located beyond said first position and by a distance whereby several rungs of the ladder means move past the level of said first guide and effective to disable said slat feeding means during the time said drive means moves said lifting element between said first and second positions; and   (vii) second retaining means at said second position to retain a stack of slats so lifted to said second position.     
     
     
       2. Apparatus as claimed in claim 1, wherein said first and second retaining means each comprise resiliently operable pawls mounted on said second guide. 
     
     
       3. Apparatus as claimed in claim 2, and further comprising means permitting adjustment of the position of said pawls. 
     
     
       4. Apparatus as claimed in claim 1, wherein said control means comprise a retractable abutment movable in the operable position, into the path of said lifting element, effective to restrain the movement of said lifting element and wherein said intermittently operable means comprise means to retract said abutment. 
     
     
       5. Apparatus as claimed in claim 4 and further comprising means permitting adjustment of the position of said retractable abutment. 
     
     
       6. Apparatus as claimed in claim 4, wherein said retractable abutment comprises an electromagnetically operated abutment pin. 
     
     
       7. Apparatus as claimed in claim 4 and further comprising an adjustable stroke limiter mounted on said lifting element and engageable with said retractable abutment to give fine adjustment of the stroke of said lifting element to said first position. 
     
     
       8. Apparatus as claimed in claim 1, wherein said drive means comprise a linear motor having a stroke bar connected to said lifting element. 
     
     
       9. A method of assembling the slats of a venetian blind in the ladder means of the blind, said method comprising the steps of: (a) providing a slat feed guide;   (b) positioning at least two ladder means with a rung of each ladder means aligned with said slat feed guide;   (c) feeding a slat or slat material to engage said so positioned rungs to assemble the slats in the ladder means and in the case of slat material subsequently cutting the slat length;   (d) lifting said assembled slat so that the next rung of each ladder means is aligned with said slat feed guide;   (e) retaining the lifted slat at said position;   (f) feeding a subsequent slat into the rungs aligned with said slat guide;   (g) repeating steps (c) through (f) several times to produce at said first position a first stack of slats;   (h) lifting the thus formed first stack to a second position located beyond said first position and by a distance whereby several rungs of the ladder means move past the level of said first guide without slats being fed thereto;   (i) retaining the stack of slats at said second position;   (j) repeating at least once the steps (b) through (e) to commence the formation of a second stack at the first position;   (k) cutting the ladder means between said first and second positions; and   (l) removing the first stack of slats from said second position, when required.   
     
     
       10. A method as claimed in claim 9, wherein after said stack engages said second retaining means, a complete second stack is formed at the first position, the slats of which are fed into the apparatus, lifted by the lifting means to the first position and held there by said first retaining means. 
     
     
       11. A method as claimed in claim 9, wherein said second stack of slats, after completion at the first position, is lifted to and retained at said second position before the first stack is completely removed therefrom.